Conveyor belt tensioning device

Abstract

The invention proposes a conveyor belt tensioning device comprising a movable carriage (350, 450, 550, 650) provided with a conveyor belt return or deflection drum (352, 452, 552, 652), at least one operating hydraulic cylinder (CC1, CC2) connected to the movable carriage (350, 450, 550, 650) for moving said carriage and adjusting a tensioning level of the conveyor belt (351, 451, 551, 651), and at least one operating hydraulic accumulator (CA1, CA2) configured to share hydraulic pressure with the operating hydraulic cylinder (CC1, CC2). The tensioning device further comprises at least one motor pump (MB5, MB6, MB7, MB8) having adjustable flow direction and magnitude of velocity, and at least one electro-hydraulic control subassembly (MC1, MC2, MC1A, MC2A, MC1B, MC2B) hydraulically connected to the operating hydraulic cylinder (CC1, CC2) and to the motor pump (MB5, MB6, MB7, MB8). The electro-hydraulic control subassembly (MC1, MC2, MC1A, MC2A, MC1B, MC2B) and the motor pump (MB5, MB6, MB7, MB8) are configured to, in real time, deliver to or remove from the operating hydraulic cylinder (CC1, CC2) a flow of hydraulic fluid determined according to the flow direction and magnitude of velocity of the motor pump (MB5, MB6, MB7, MB8), wherein, in a first structural arrangement of the tensioning device, the hydraulic fluid flow originates from or is directed to a hydraulic reservoir, at different tensioning levels of the conveyor belt (351, 451, 551, 651), or, in a second structural arrangement of the tensioning device, at least one energy recovery hydraulic accumulator (CA3, CA4) is hydraulically connected to the motor pump (MB5, MB6, MB7, MB8) and to the electro-hydraulic control subassembly (MC1, MC2, MC1B, MC2B), and the hydraulic fluid flow originates from the energy recovery hydraulic accumulator (CA3, CA4) to supply hydraulic energy to the operating hydraulic cylinder (CC1, CC2), or is directed to the energy recovery hydraulic accumulator (CA3, CA4) for storage of hydraulic energy, at different tensioning levels of the conveyor belt (351, 451, 551, 651).

Description

[0001] "CONVEYOR BELT TENSIONING DEVICE"

[0002] Technical field

[0003]

[0001] The present invention relates to the field of conveyor belts and, more specifically, to a device that uses a hydraulic system capable of maintaining the conveyor belt properly tensioned under its various conditions of use.

[0004] State of the art

[0005]

[0002] As is well known regarding the tensioning required for the proper operation of conveyor belts, the conditions are: - This can be adjusted by splitting one of the drums at its ends, as well as through the use of one or more belt deflection rollers, most commonly found on its return side (the side that is permanently unloaded during transport).

[0006] - The curve of required tension values ​​over time shows significant variations. Except for very complex conveyors, these variations relate to six possible situations regarding conveyor operation:

[0007] - Carrier at rest;

[0008] - Accelerating conveyor with electro-hydraulic control (normal start);

[0009] - Carrier operating on a constant and stable schedule;

[0010] - Conveyor operating at a steady but unstable rate (e.g., significant transient pulses or drops in the cargo being transported);

[0011] - Conveyor in braking mode, with electro-hydraulic control (normal stop);

[0012] - Carrier in emergency braking, without electrical control (sudden stop due to power outage).

[0013]

[0003] There are several conveyor design features that influence the values ​​for each of the situations described above, such as: - Height of the drive drum in relation to the return drum;

[0014] - Transport height profile (horizontal, ascending, mixed with horizontal at the beginning, mixed with horizontal at the end, mixed and with alternating heights);

[0015] - Position and method of loading (material entry into the conveyor) in relation to the motor drum;

[0016] - Type adopted for belt tensioning.

[0017]

[0004] The constructive characteristics of the project, taken together, can even determine the direction of the transient voltage pulse / drop in a given operating situation, in relation to the steady-state voltage and the position of the tensioning element.

[0018]

[0005] The most traditional way to obtain conveyor belt tension is with the use of a mechanical counterweight, as shown in figure 1, developed by the American company Joy Manufacturing Co., which adopts a value that best suits all needs, since this value cannot be changed during the process.

[0019]

[0006] Hydraulic systems have been used for tensioning conveyor belts since at least 1963, with numerous publications on this subject since then. Their use in place of gravity tensioners (mechanical counterweights) often allows for the achievement of three major design objectives, among others:

[0020] - Reducing the space occupied by the counterweight, cables, and pulleys;

[0021] - The highest level of safety in case of component failures, due to the lower moving masses;

[0022] - The ability to automatically adjust the tension level in different working situations, especially during emergency stops.

[0023]

[0007] In order to meet these objectives, two main elements are found repeatedly in the various known and publicly available configurations:

[0024] - The use of one or more hydraulic cylinders as actuators in the fractionation of the drum carrier carriage that tensions the belt, or in conjunction with auxiliary devices;

[0025] - The use of one or more hydraulic accumulators as energy storage elements, to be used in different ways depending on the phase of the process.

[0026]

[0008] As typical examples of the above, we cite invention patents US4007826A and US 10696486.

[0027]

[0009] A 1963 system, published with Figure 2, developed by the American company Joy Manufacturing Co., already shows the use of a hydraulic operating cylinder and a hydraulic operating accumulator in a simple system, yet still used today in conveyors with small load oscillations over time, especially fully horizontal ones. The correct dimensioning of the hydraulic accumulator in this system and its load already allows, in many types of processes, an automatic adjustment of the tension according to the need at each moment, at more appropriate levels than with the use of a mechanical counterweight. The well-dimensioned accumulator can generate a large increase in tension for a given displacement of the cylinder when it is pulled by the conveyor belt, but as it is a passive adjustment system, this adjustment does not anticipate the change in the transverse sag of the belt, but only reacts to its existence.Thus, in a critical case of backlash generation, such as in a sudden emergency stop on a mixed conveyor with a horizontal initial section and an ascending final section, the accumulator load must already be oversized, even under stabilized operating conditions, to prevent an increase in these backlashes from the start of the stop, which leads to a reduction in the service life of the conveyor belt and other components subjected to the resulting tension.

[0028]

[0010] US patent 4007826A, from 1977, shows an improvement in methods of controlling stored energy, including the use of two levels of hydraulic accumulators: an operating hydraulic accumulator and an emergency hydraulic accumulator, which operates at a higher pressure level and is used only in emergency shutdown situations or due to power outages, mainly in mixed conveyors, as in the case focused on in this patent. The formation of localized belt tension faults (transverse deflections that cause bulk spillage and damage to equipment) due to differences in the inertia of the moving materials during a sudden stop is avoided through the immediate application of a higher tension level, activated by the power outage itself. Under these conditions, a shorter emergency braking time for the moving masses is also obtained.During regular operation, the tension level is kept lower, favoring the service life of the belt and other stressed components. However, as it is also a passive system, during regular operation, the precision in achieving the correct tension and adjustment due to transverse sag is limited. These sags can vary greatly throughout the entire transport path and on the return of the belt, and are proportionally different from the fractional value applied to the tensioning element.

[0029]

[0011] US patent 10696486, from 2020, also seeks to compensate for tension failures in emergency stops, but using only one level of hydraulic accumulator operation. For this purpose, it adds restriction valves to generate an increase in tension in the intermediate phase of emergency stops where there is an effect of increasing the hydraulic cylinder's tension, with the beginning and end of the stop at the same level of the hydraulic accumulator, as in the 1963 system. In conveyors where the emergency stop does not generate an effect of increasing the hydraulic cylinder's tension, the said restriction valves do not operate, and thus this device behaves as in the 1963 device.Consequently, it does not fully replace the improvement permitted by US patent 4007826A, and since it is also a passive system during regular operation, the accuracy in proper tensioning and the resulting adjustment of transverse deflections is similarly limited.

[0030]

[0012] The patents cited above have hydraulic accumulators that allow some type of tension increase depending on the change in position of the tensioning element and the speed at which this change is made, but are not suitable for conveyors with more complex processes, where there may be a large variation in the force required for transport with the same critical clearance condition. When used in these cases, the maximum tension value of the conveyor belt must be oversized to maintain an adequate level of transverse belt deflection at any time during regular operation, with a corresponding burden on the service life of the conveyor components.

[0031]

[0013] The state of the art also includes, as an alternative to hydraulic cylinders, the use of electric or hydraulic winches for direct fractionation of the carriage that drives the free drum, responsible for tensioning the belt. Such winches do not include energy storage systems and have very high inertia for faster response actuations. Because of this, these solutions are used in applications with lower dynamic requirements, and without the resources discussed previously.

[0014] As discussed earlier, the hydraulic systems used in conveyor belt tensioning devices normally operate with the adjustment of the operating tension level limited to the capacity of the operating hydraulic accumulator, or use conventional resources that result in dissipation of hydraulic energy during significant tension changes.Furthermore, such systems do not allow for an adequate response to large dynamic load variations, hindering the efficient adaptation of the tension level in operating conditions present in belt conveyors that have a higher level of dynamic response requirements.

[0032] Summary of the Invention

[0033]

[0015] The main objective of the invention is a type of stretching that can be adapted to each specific project, providing controlled tension based on transverse deflections located at specific points or other criteria considered more critical in the overall project.

[0034]

[0016] The objective of the present invention is an improvement in a device for tensioning conveyor belts, using a hydraulic system specifically configured to:

[0035] - To remain active and independent throughout the regular transport process, whenever the application requires it, maintaining substantially higher energy efficiency than equivalent systems from the prior art;

[0036] - To be applicable to any operating condition and any type of construction of these conveyors, maintaining the conveyor belt at an allowable deflection level equal to or less than that granted by the prior art in this respect, in similar applications.

[0037]

[0017] The invention proposes a conveyor belt tensioning device comprising a mobile carriage equipped with a conveyor belt return or deflection drum, at least one operating hydraulic cylinder connected to the mobile carriage to move said carriage and adjust a conveyor belt tension level, as well as at least one operating hydraulic accumulator configured to share hydraulic pressure with the operating hydraulic cylinder. According to the invention, the tensioning device further comprises at least one motor pump with adjustable flow direction and speed magnitude, and at least one electro-hydraulic control subassembly hydraulically connected to the operating hydraulic cylinder and the motor pump. The electro-hydraulic control subassembly and the motor pump are configured to, in real time,Transfer to or remove from the operating hydraulic cylinder a flow rate of hydraulic fluid obtained as a function of the flow direction and speed magnitude of the motor pump, wherein, in a first constructive configuration of the tensioning device, the hydraulic fluid flow originates from or is destined for a hydraulic reservoir, in adjustments distinct from the tensioning level of the conveyor belt, or, in a second constructive configuration of the tensioning device, at least one hydraulic energy recovery accumulator is hydraulically connected to the motor pump and the electro-hydraulic control subassembly, and the hydraulic fluid flow originates from the hydraulic energy recovery accumulator to supply hydraulic energy to the operating hydraulic cylinder or is destined for the hydraulic energy recovery accumulator for hydraulic energy storage.The tensioning device allows for distinct adjustments of the conveyor belt tension level. Thus, it enables active control of the belt tension level during regular operation, independent of changes in the cylinder position, and offers high responsiveness in highly dynamic situations. Furthermore, the electro-hydraulic control subassembly allows for a faster and more efficient response to operational variations in the belt, contributing to greater stability of the conveyor system, reduced wear on mechanical and hydraulic components, and increased overall energy efficiency of the tensioning device.

[0038]

[0018] Furthermore, according to the second constructive configuration equipped with the hydraulic energy recovery accumulator, the tensioning device allows for the local recovery of hydraulic energy associated with variations in the tension level of the conveyor belt, reducing energy losses and decreasing the energy demand supplied by the motor pump in subsequent adjustments, in addition to contributing to the reduction of installed power in belt conveyors subjected to large dynamic load variations. Active control allows for large variations in the operating accumulator load, controlled in real time, but without resorting to the use of very high drive powers that would be necessary in traditional solutions.This is made possible by the use of a regenerative drive system, which allows for the reuse of a large portion of the energy used in increasing or decreasing tension during the regular process. This energy recovery, stored in the hydraulic energy recovery accumulator, allows for very high actuation power of the mobile carriage that tensions the conveyor belt in a short period, meeting momentary demands of high dynamics, independent of the actuator's position, in any conveyor configuration and momentary distribution of specific loads along the transport path, where the corresponding traditional solution requires the use of high installed power.

[0039]

[0019] The invention also includes auxiliary elements to adapt the basic assembly to the specific conditions of very long and elastic conveyors, or very short and rigid ones.

[0040] Brief description of the Figures

[0041]

[0020] In order that the present invention may be fully understood and put into practice by any technician in this technological sector, it is described in a clear, precise and sufficient manner, based on the drawings listed below:

[0042] Figure 1 - Schematic diagram of a conventional conveyor belt tensioning device, operating in the vertical direction and actuated by a mechanical counterweight;

[0043] Figure 2 - Schematic diagram of a conventional conveyor belt tensioning device, operating horizontally and actuated by a hydraulic cylinder;

[0044] Figure 3A - Diagrammatic side view of a conveyor belt tensioning device, operating horizontally and actuated in a combined manner by hydraulic cylinders and auxiliary stage actuation devices;

[0045] Figure 3B - Diagrammatic top view of a conveyor belt tensioning device, operating horizontally and actuated in a combined manner by hydraulic cylinders and auxiliary stage actuation devices; Figure 4A - Diagrammatic side view of a conveyor belt tensioning device, operating horizontally and actuated in a combined manner by hydraulic cylinders and auxiliary winches; Figure 4B - Diagrammatic top view of a conveyor belt tensioning device, operating horizontally and actuated in a combined manner by hydraulic cylinders and auxiliary winches; Figure 5A - Side view detail of the mobile carriage that carries the tensioning drum;

[0046] Figure 5B - Top view detail of the mobile carriage carrying the tensioning drum, with the carriage remaining aligned with the rails;

[0047] Figure 5C - top view of the mobile carriage carrying the stretching drum, with the carriage slightly rotated relative to the rails;

[0048] Figure 6 - Block diagram representing the constituent subassemblies of a hydraulic conveyor belt tensioning control configuration and their interconnections according to an embodiment of the invention;

[0049] Figure 7 - Hydraulic tension control scheme for the left side of the conveyor belt and its hydraulic energy storage system according to the embodiment illustrated in Figure 6;

[0050] Figure 8 - Hydraulic tension control scheme for the right side of the conveyor belt, and its hydraulic energy storage system according to the incorporation illustrated in Figure 6;

[0051] Figure 9 - Hydraulic scheme for charging the accumulators and controlling the actuation of stored hydraulic energy for conveyor belt shutdowns due to electrical power outages, according to the incorporation illustrated in Figure 6;

[0052] Figure 10 - Hydraulic control diagram of the auxiliary mechanism for staged actuation of the left side tensioning of the conveyor belt;

[0053] Figure 11 - Hydraulic control diagram of the auxiliary mechanism for staged actuation of the tensioning of the right side of the conveyor belt;

[0054] Figure 12A - Diagrammatic side view of a conveyor belt tensioning device, operating horizontally and actuated in a combined manner, by 2 cylinders linked in series with 1 single auxiliary actuation device in stages, for each side of the tensioner; Figure 12B - Diagrammatic top view of a conveyor belt tensioning device, operating horizontally and actuated in a combined manner, by 2 cylinders linked in series with 1 single auxiliary actuation device in stages, for each side of the tensioner; Figure 13A - Diagrammatic side view of a conveyor belt tensioning device, operating vertically and actuated by 8 hydraulic cylinders, which are arranged 2 by 2 in a series chain of pairs;

[0055] Figure 13B - Diagrammatic top view of a conveyor belt tensioning device, operating vertically and actuated by 8 hydraulic cylinders, which are arranged in pairs in a series of doubles;

[0056] Figure 14 - Hydraulic control scheme for tensioning the left side of the conveyor belt and its hydraulic energy storage system - variant with controls separated into 2 blocks; Figure 15 - Hydraulic control scheme for tensioning the right side of the conveyor belt and its hydraulic energy storage system - variant with controls separated into 2 blocks; Figure 16 - Hydraulic control scheme for a single auxiliary device with step-actuation, in the tensioning of the left side of the conveyor belt;

[0057] Figure 17 - Hydraulic control diagram for a single auxiliary device operating in stages, for tensioning the right side of the conveyor belt;

[0058] Figure 18 - Block diagram representing the constituent subassemblies of the hydraulic control configuration of the invention and their interconnections - variant with operational controls separated into 4 blocks, 2 for each side, and with controls for 2 auxiliary stage actuation devices on each side of the tensioner; Figure 19 - Block diagram representing the constituent subassemblies of the hydraulic control configuration of the invention and their interconnections - variant without the operational energy storage system and with controls for 1 single auxiliary stage actuation device on each side of the tensioner;

[0059] Figure 20 - Block diagram representing the constituent subsets of the hydraulic control configuration of the invention for 4 sets of actuators chained in compact series and their interconnections - variant without the operational energy storage system and without controls for auxiliary devices.

[0060] Detailed description of the invention

[0061]

[0021] The hydraulic components of the invention have symbology in accordance with ISO 1219, to enable precise identification of each typical logic configuration.

[0062]

[0022] The invention proposes a conveyor belt tensioning device comprising a mobile carriage (350, 450, 550, 650) equipped with a conveyor belt return or deflection drum (352, 452, 552, 652), at least one operating hydraulic cylinder (CC1, CC2) connected to the mobile carriage (350, 450, 550, 650) to move said carriage and adjust a conveyor belt tension level (351, 451, 551, 651), as well as at least one operating hydraulic accumulator (CA1, CA2) configured to share hydraulic pressure with the operating hydraulic cylinder (CC1, CC2). According to the invention, the tensioning device further comprises at least one motor pump (MB5, MB6, MB7, MB8) having adjustable flow direction and speed magnitude, and at least one electro-hydraulic control subassembly (MC1, MC2, MC1A, MC2A, MC1B, MC2B) hydraulically connected to the operating hydraulic cylinder (CC1, CC2) and to the motor pump (MB5, MB6, MB7,MB8). The electro-hydraulic control subassembly (MC1, MC2, MC1A, MC2A, MC1B, MC2B) and the motor pump (MB5, MB6, MB7, MB8) are configured to transfer, in real time, to or remove from the operating hydraulic cylinder (CC1, CC2) a flow rate of hydraulic fluid obtained as a function of the flow direction and speed magnitude of the motor pump (MB5, MB6, MB7, MB8). In a first constructive configuration of the tensioning device, the hydraulic fluid flow originates from or is destined for a hydraulic reservoir, in settings distinct from the tensioning level of the conveyor belt (351, 451, 551, 651). In a second constructive configuration of the tensioning device, at least one hydraulic energy recovery accumulator (CA3, CA4) is hydraulically connected to the motor pump (MB5, MB6, MB7, MB8) and to the... electro-hydraulic control subset (MC1, MC2, MC1B,MC2B) and the hydraulic fluid flow originates from the hydraulic energy recovery accumulator (CA3, CA4) to supply hydraulic energy to the operating hydraulic cylinder (CC1, CC2) or is destined for the hydraulic energy recovery accumulator (CA3, CA4) for hydraulic energy storage, in different adjustments of the conveyor belt tensioning level (351, 451, 551, 651). Figures 19 and 20 illustrate examples of incorporations according to the first constructive configuration of the tensioning device, respectively, while Figures 6 and 18 illustrate examples of incorporations according to the second constructive configuration of the tensioning device.

[0063]

[0023] Every conveyor belt begins its adjustment with a pre-tensioning of the conveyor belt at rest, to a level considered most suitable for the configuration of the conveyor and the tensioning device used. With the use of the device described in this invention, pre-tensioning is done with a minimum value to be required in any situation of regular, emergency or rest operation, in addition to the tensioning variations required during regular operation. This pre-tensioning will be referred to here as Tmin tensioning, and must be adjusted with the rod of the operating hydraulic cylinder (C1, C2) in a position close to the least actuation - rod almost fully extended, for cylinders that tension by fractioning, or rod almost fully retracted, for cylinders that tension by compressing.

[0064]

[0024] To achieve the proper position of the operating hydraulic cylinder (C1, C2), together with the appropriate tension Tmin, several methods are possible, including manual tensioning with external equipment. Figures 3A, 3B, 4A, 4B, 5A, 5B, 5C, 12A and 12B show diagrammatic views of auxiliary elements used in the horizontal tensioning of conveyor belts, which represent the main forms for the tension Tmin of the various configurations of this type of conveyor, in combination with the use of the main tensioning device conceived in the present invention.

[0065]

[0025] According to an embodiment of the invention, the tensioning device has a configuration expansion for use in medium-distance conveyors, to perform a pre-tensioning of the conveyor belt (351), manually, semi-automatically or automatically, during the initial adjustment of the conveyor, combining with the complementary subassemblies (MC7, MC8), with auxiliary hydraulic tensioning cylinders (CC3, CC4) and auxiliary hydraulic keying cylinders (CC5, CC6, CC7, CC8), and with the auxiliary hydromechanical keying mechanisms (301 and 302), wherein in the regular operation of this expansion of the basic configuration, the operating hydraulic cylinders (CC1 and CC2) fraction the moving carriage (350) that tensions the conveyor belt (351), indirectly through toothed bars (341, 344) connected by keys (361, 364), which are kept advanced by the auxiliary hydraulic keying cylinders. (CC5, CC6),The auxiliary hydraulic tensioning cylinders (CC3, CC4) also move the mobile carriage (350) during maintenance activities with tension below the minimum required for regular operation of the conveyor belt (351), provided that their toothed bars (342, 343) are engaged in the carriage (350) by the keys (362 and 363), which are advanced by the auxiliary hydraulic keyway cylinders (CC7, CC8). During maintenance activities, the mobile carriage (350) is moved in stages through the alternating and cyclical action between the operating cylinders (CC1, CC2) and the auxiliary tensioning cylinders (CC3, CC4), also involving the keyway cylinders (CC5, CC6, CC7, CC8) for engaging or disengaging each toothed bar (341, 342, 343, 344), according to the moment of the displacement cycle, each one being... These maintenance movements are executed with the registers (RG1, RG3) closed.With the 4 / 3 directional valve (VD0) actuated, and with a directional valve solenoid (VP1, VP2, VP3, VP4, VP7, VP8) actuated, according to the movement, and requiring the actuation of the specific directional valve for each movement: auxiliary tensioning directional valve (VD3, VD4), to move the auxiliary tensioning hydraulic cylinders (CC3, CC4) respectively; auxiliary keyway directional valve (VD5, VD6, VD7, VD8), to move the auxiliary keyway hydraulic cylinders (CC5, CC6, CC7, CC8) respectively; and the electric directional valves (VP1, VP2, VP3, VP4, VP7, VP8) together with the blocking directional valves (VD1, VD2), to move the operating hydraulic cylinders (CC1, CC2) respectively.

[0066]

[0026] Figures 3A and 3B show a method for performing the tensioning Tmin of the conveyor belt (351), using two intermittently actuating hydromechanical mechanisms (301 and 302) to divide the carriage (350) that drives the drum (352). Each of these mechanisms is actuated manually, semi-automatically or automatically by two parallel hydraulic cylinders (CC1 and CC3 for mechanism 301; CC2 and CC4 for mechanism 302), located near one side of the moving carriage (350). Each of these pairs of cylinders is articulated on the base (300), anchored to the conveyor structure, and alternates between them to move the respective side of the carriage (350) in stages. This occurs through the toothed bars (341 and 342 for mechanism 301; 343 and 344 for mechanism 302).The engagement and release of each toothed bar to the moving carriage (350) is carried out by four other cylinders (CC5, CC7, CC8 and CC6) arranged at 90° in relation to the four fractioning cylinders (CC1, CC3, CC4 and CC2), by means of the positioning of the keys (361, 362, 363 and 364), guaranteed by redundant electrical sensing. Each stage of simultaneous displacement of the toothed bars (341, 342, 343 and 344), two by two, corresponds to an increment of fractionation of the moving carriage (350), which tensions the conveyor belt (351). The carriage (350) preferably has four sets of wheels (353) with an articulation axle (354). For this purpose, it is possible to use all the sub-assemblies shown in figures 6, 10 and 11, detailed further on.

[0067]

[0027] According to an embodiment of the invention, the tensioning device has an expanded configuration for use in long-distance conveyors or conveyors with high elasticity under tension, to perform a pre-tensioning of the conveyor belt, manually, semi-automatically or automatically, during the initial commissioning of the conveyor, using the operating hydraulic cylinders (CC1, CC2) to directly divide the moving carriage (450), its other ends being articulated in an intermediate moving carriage (440), which in turn is kept tractioned by an electric or hydraulic winch (411, 412), anchored to the fixed structure of the conveyor, through a base (400), this winch acting only for the execution of the pre-tensioning of the conveyor belt (451), remaining inactive and braked during the regular operation of the conveyor.

[0068]

[0028] Figures 4A and 4B show a method for performing the Tmin tensioning using winches (411 and 412), which can be electric or hydraulic. These winches are anchored to the loader's fixed structure via the base (400) and employ steel cables (421 and 422) with articulations (426) to traction an intermediate mobile carriage (440), which in turn fractions the cylinders (CC1 and CC2), applying the Tmin tension to each of these cylinders, which transmit it to the mobile carriage (450), which tensions the conveyor belt (451), similar to that illustrated in Figures 3A and 3B. The tensioning elements of Figures 4A and 4B contain redundant electrical sensing to ensure the activation of the negative brake of each winch. The intermediate mobile carriage (440) moves on four wheels (443), which are supported and guided on two parallel rails. The parallel hydraulic cylinders (CC1 and CC2) consist of the body (434), rod (435) and end lugs (433 and 436).

[0069]

[0029] The Tmin tensioning mechanism, as shown in Figures 3A and 3B, is more appropriate for medium-distance conveyors, where the working stroke of the moving carriage (350) is too long to use hydraulic cylinders alone, but not too long to use toothed bars (341, 342, 343 and 344). And there are possible variants with twice the number of cylinders, actuated in parallel, and arranged half above and half below the conveyor belt (351), thus enabling a significant reduction in space occupied.

[0070]

[0030] The tensioning solution Tmin, shown in figures 4A and 4B, is more appropriate for long-distance conveyors, where the working stroke of the moving carriage (450) is excessive even for the use of toothed bars (341, 342, 343 and 344), but generally occupy more space or cause greater difficulties in the mechanical design layout.

[0071]

[0031] In short-distance conveyors, or where the conveyor belt (or similar) has very low elasticity, it becomes possible to use the hydraulic cylinders (CC1 and CC2) directly, without the need for toothed bars (341, 342, 343 and 344), or any other auxiliary elements for tensioning Tmin.

[0072]

[0032] According to an embodiment of the invention, the mobile carriage (350 and 450) comprises four pairs of wheels (353, 453), which move on two parallel rails (TR1), each pair in the same running plane, which is articulated in relation to the body of the mobile carriage (350, 450), around a pivot center (CG1), up to a limit of the running clearances (FG1), to allow a deviation of perpendicularity between a drum axis (352, 452) and a conveyor belt transport axis (351, 451), generated by differential tension between the two sides (left and right) of the mobile carriage (350, 450), actuated respectively by the operating hydraulic cylinders (CC1, CC2), directly or indirectly, each having an active and independent electro-hydraulic control, during the regular operation of the conveyor, aiming to compensate for misalignments of this belt.

[0073]

[0033] As illustrated in figures 5A, 5B and 5C, the mobile car (350 and 450) moves on four sets of wheel pairs (353 and 453), which are supported and guided on two parallel rails (TR1), with lateral clearances, each pair of wheels in the same plane of rotation, which is articulated in relation to the body of the mobile car (350 and 450), around the center of rotation (CG1), up to the limit of the rotation clearances (FG1) allowed by the design, all in such a way as to allow a small deviation of perpendicularity between the axis of the drum (352 and 452) and the transport axis of the conveyor belt (351 and 451), generated by differential tension between the sides (Left and Right) of the mobile car's (350 and 450) division, through active and independent electro-hydraulic controls for each side, carried out on the hydraulic cylinders (CC1 and CC2), aiming to compensate for conveyor belt misalignments (351 and 451), during regular operation.Figure 5C shows a top view of the moving carriage (350 and 450), where this carriage is rotated counterclockwise from this view, with the Clearance (FG1) of Detail D3 shifted all the way to the Right side of the carriage, while in Detail D4 it is shifted all the way to the Left side of this carriage.

[0074]

[0034] The block diagram in Figure 6 shows the hydraulic connections between the constituent subassemblies of the hydraulic control scheme according to an embodiment of the invention, including the independent controls for each side (Left and Right Sides) of the conveyor belt (350 and 450). Thus, in simplified configurations, with simultaneous controls for all cylinders, or with a single centralized control, the subassemblies (CC2, CC4, CA2, CA4, MC2 and MB6) in this block diagram can be omitted. All subassemblies of the block diagram in Figure 6 are described in detail in the following figures and descriptions.

[0075]

[0035] Figure 7 shows in detail the subassemblies (MB5 and MC1) and the hydraulic connections between them, with the hydraulic cylinder (CC1), and with the hydraulic accumulators (CA1 and CA3). This figure also shows the connections (C15 and P1) that connect the subassembly (MC1) with the subassembly (MC3) - see figure 6. These subassemblies are responsible for tension control on the left side of the conveyor belt (351 and 451), and for its energy storage system, for regular operation of this tensioning.

[0076]

[0036] Figure 8 shows in detail the subassemblies (MB6 and MC2) and the hydraulic connections between them, with the hydraulic cylinder (CC2), and with the hydraulic accumulators (CA2 and CA4). This figure also shows the connections (C25 and P2) that connect the subassembly (MC2) with the subassembly (MC3) - see figure 6. These subassemblies are responsible for tension control on the right side of the conveyor belt (351 and 451), and for its energy storage system, for regular operation of this tensioning.

[0077]

[0037] According to an embodiment of the invention, the tensioning device comprises a set of pressure transducers (PR1, PC1, PB5, PD1, PA3, P07, PR2, PC2, PB6, PD2, PA4, P08) to monitor pressure at key points of the electro-hydraulic control subassemblies (MC1, MC2, MC1A, MC2A, MC1B, MC2B), allowing precise tensioning controls at any time, and alarm and safety lockout routines in the event of failures.

[0078]

[0038] According to one embodiment of the invention, the tensioning device comprises a relief valve (VA1, VA2) to limit a maximum recoil pressure value of the operating hydraulic cylinder rods (CC1, CC2), and a relief valve (VA9, VA10) to limit a maximum advance pressure value of the operating hydraulic cylinder rods (CC1, CC2), during pre-tensioning or maintenance activities, wherein a check valve (RG1, RG2) allows for the tight blocking of the volume stored in the operating accumulators (CA1, CA2), during maintenance activities.

[0079]

[0039] According to one embodiment of the invention, the tensioning device comprises a normally closed, 2 / 2 directional shut-off valve (VD1, VD2) for blocking oil flow, in the absence of electrical control, between the hydraulic actuation subassemblies (CC1 + PC1 + CA1 and CC2 + PC2 + CA2) and their respective control components, a shut-off valve (RG7, RG8) for isolating the operating hydraulic cylinder (CC1, CC2) and / or a shut-off valve (RG9, RG10) for discharging the volume stored in that region to the hydraulic reservoir during an emergency stop, rest period or maintenance activities, and a shut-off valve (VB3, VB4), actuated by internal differential pressure control, allows a function of blocking excess flow output from the operating hydraulic cylinders (CC1, CC2) during the extension of their rods, redundant to that already permitted electrically with the pressure transducers (PC1 and PD1 on valve VD1;PC2 and PD2 on the VD2 valve).

[0080]

[0040] According to one embodiment of the invention, the tensioning device has logic elements (EL1, EL2), hydraulically connected to the operating hydraulic cylinders (CC1, CC2), to draw hydraulic fluid from the hydraulic reservoir when the operating hydraulic cylinders (CC1, CC2) are reducing the tension of the conveyor belt (351, 451, 551, 651), with the pilot directional valves (VP1, VP2, VP3, VP4, VP7, VP8) being deactivated, when said logic elements (EL1, EL2) have adequate opening pressure for said suction function, when the check valves (VR3, VR4) block the access of atmospheric pressure existing in the hydraulic reservoir to the logic elements (EL1, EL2), and in the reverse movement, when the operating hydraulic cylinders (CC1, CC2) need to expel the drawn fluid, monitored by pressure transducers. (PR1, PR2), when an increase in conveyor belt stretching occurs (351,451, 551, 651), the logic elements (EL1, EL2) are also opened, with the fluid contained in the pilot chamber of the logic elements (EL1, EL2) being discharged to the hydraulic reservoir, along with the flow through the jet of its piston, passing through the center of the pilot directional valves (VP1, VP2, VP3, VP4, VP7, VP8) and the check valves (VR3, VR4), which allows the logic elements (EL1, EL2) to open.

[0041] According to one embodiment of the invention, the tensioning device comprises at least one check valve (VR9, VR10) to protect against reverse flow over the motor pump (MB5, MB6, MB7, MB8), when the motor pump (MB5, MB6, MB7, MB8) does not operate bidirectionally.

[0081]

[0042] According to one embodiment of the invention, the tensioning device has an emergency hydraulic accumulator (CA5) for emergency stops, its pressure monitoring transducer (PA5), an auxiliary pumping subassembly (MBO), which provides the initial hydraulic charge of the operating hydraulic accumulators (CA1, CA2), energy recovery (CA3, CA4) and emergency (CA5), and an electro-hydraulic control subassembly (MC3), which together with the pressure transducers (PAO, PBO, PA3, PA4, PA5), the pressure gauge (MNO), and its isolation register (RBO), provide control of the minimum hydraulic charge of said accumulators (CA1, CA2, CA3, CA4, CA5), in addition to controlling the actuation of the operating hydraulic cylinders (CC1 and CC2) in emergency stops, wherein the emergency hydraulic accumulator (CA5) remains inactive, despite being charged, during the regular operation of the conveyor,Entering the operating circuit of the hydraulic cylinders (CC1, CC2) automatically during emergency power outages, the control valve (VC5) opens in a ramped fashion, with its time controlled by a jet (G50) that controls the flow rate of the valve (VC5) actuation, from the moment its 4 / 2 pilot directional valve (VP5) is switched off by the power outage. The opening of the control valve (VC5) provides a direct connection of the emergency hydraulic accumulator (CA5) to the operating hydraulic cylinder (CC1, CC2) and the operating hydraulic accumulators (CA1, CA2), without interference from the energy recovery hydraulic accumulators (CA3, CA4), which are isolated by the automatic blocking of the 2 / 2 blocking directional valves (VD1, VD2) during a power outage. In a regular (non-emergency) shutdown event...The 4 / 2 directional valve (VD9) is activated at the beginning of this shutdown and remains activated until its end, allowing the complete discharge of the fluid stored in the emergency hydraulic accumulator (CA5) through the compensated jet (GC9). The emergency hydraulic accumulator (CA5) has a relief valve (VA5) to limit its maximum charge and a gate valve (RG5) to securely block the volume stored in the emergency hydraulic accumulator (CA5) during maintenance activities.

[0082]

[0043] Figure 9 shows in detail the motor pump subassembly (MBO) and the hydraulic accumulator control subassembly (MC3) (CA5), as well as the hydraulic connection between them, for emergency shutdowns. This figure also shows the connections (A31 and A51) that connect subassembly (MC3) with subassembly (MC1), and the connections (A42 and A52) that connect subassembly (MC3) with subassembly (MC2) - see Figure 6. Subassemblies (MBO and MC3) are responsible for charging all accumulators and storing energy for emergency shutdowns.

[0083]

[0044] In the emergency hydraulic accumulator (CA5), a constant pressure will always be maintained during regular operation, and will only be discharged during emergency stops, when the electrical power supplying all the conveyor's controls and motors is cut off. This discharge occurs through the control valve (VC5), which has a gradual opening based on the displacement of its piston, and which is controlled by the directional valve (VP5). The directional valve (VP5) is kept electrically actuated throughout the regular operation of the conveyor, thus keeping the control valve (VC5) closed. The minimum time for the control valve (VC5) to fully open is less than 30 ms, in any type and capacity of these conveyors, thus being much shorter than the stopping time of large masses being transported, due to the large difference in inertia between the two systems.Consequently, adjustment is required to generate a ramp-like response between the two systems – in the event of a power outage, the directional valve (VP5) is switched off, causing the control valve (VC5) to open in a ramp-like fashion with a time controlled by the jet (G50), suitable for each specific application. The discharged flow is used to increase the charge of the accumulators (CA2 and CA4) in a controlled manner, and also in accordance with the other elasticity characteristics of the system as a whole.

[0084]

[0045] The pressure value of the volume stored in the emergency hydraulic accumulator (CA5), and its ratio to the stabilized regular operating pressure, is highly dependent on each specific conveyor design and may even be lower than the pressure in the hydraulic cylinder (CC1 and CC2) at the time of the power outage.

[0085]

[0046] In a regular (non-emergency) shutdown event, the valve (VD9) is activated at the beginning of this shutdown and remains activated until its end, allowing the complete discharge of the fluid stored in the accumulator (CA5) through the compensated jet (GC9). The general control system considers that the end of the regular shutdown occurs only when the conveyor is completely stopped, with the pressure of the pressure transducer (PA5) within the permitted range for stored energy in no-load conditions, and with the pressure of the operating pressure transducers (PC1 and PC2) within the permitted range for resting pressure - see figures 7 and 8.

[0086]

[0047] The motor-pump subassembly (MBO) provides power for the initial charging of all hydraulic accumulators, via the directional (VDO) and transducers (PA3, PA4 and PA5) that monitor the pressure of each accumulator, in figures 7, 8, 9, 14 and 15, and for small recharges during the regular process, replacing losses due to drains and internal leakage, permitted in some secondary components. These losses are not permitted in components of the main circuit, which remains pressurized at rest, maintaining the conveyor belt tension condition unchanged, as determined at the last stop.

[0087]

[0048] The pressure in the regenerative hydraulic accumulators (CA3 and CA4) during regular operation will always be lower than in the operating hydraulic accumulators (CA1 and CA2), where pressures are always adjusted in real time to suit the tensioning needs of each moment. If a situation occurs (which may happen after maintenance) where the charge in the hydraulic accumulator (CA1) is lower than the charge in the hydraulic accumulator (CA3), the hydraulic accumulator (CA1) will be automatically charged via the retention valve (VR1). An identical process occurs between the hydraulic accumulators (CA2 and CA4) and the retention valve (VR2).

[0088]

[0049] According to one embodiment of the invention, the tensioning device comprises at least one relief valve (VA7, VA8) piloted by a respective proportional pressure valve (PP1, PP2) to perform a redundancy of pressure control of the operating hydraulic cylinders (CC1, CC2), and simultaneously provide a recovery of fluid volumes eventually removed from the operating hydraulic cylinders (CC1, CC2), which are directed to storage in the hydraulic energy recovery accumulators (CA3, CA4).

[0089]

[0050] According to an embodiment of the invention, the energy recovery accumulators (CA3, CA4) are protected from overload by a relief valve (VA3, VA4), the tensioning device further comprising a check valve (RG3, RG4), to hydraulically block the hydraulic energy recovery accumulator (CA3, CA4) in a watertight manner during maintenance activities, and protection against possible excess discharge flow from the hydraulic energy recovery accumulator (CA3, CA4), by automatically blocking this flow, through exclusively hydraulic sensing and actuation of a 2 / 2 directional valve (VB1, VB2).

[0090]

[0051] Referring back to Figure 7, the pressure increase in the hydraulic accumulator (CA1), and consequently also in the hydraulic cylinder (CC1), during regular operation, is achieved with the directional valve (VD1) actuated, and with a value determined by the proportional pressure valve (PP1), which adjusts the desired increase over the minimum pressure manually defined in the relief valve (VA7), adjusted slightly below the preload value (PG1) of the hydraulic accumulator (CA1). The pressure of the relief valve (VA3) always remains adjusted to the maximum load value allowed in the hydraulic accumulator (CA3). An electric motor with a frequency inverter, or other drive with the same features, maintains the pump rotation (B5) at a level compatible with the dynamic requirements of each phase of regular operation.Since this pump is powered by the hydraulic accumulator (CA3), its function is solely to perform a pressure boost when necessary, consuming power only for this purpose, resulting in much lower installed power compared to traditional systems for the same level of response. In situations requiring high precision and very high dynamics, the motor pump (MB5) maintains rotation with excess flow at any given moment. Under these demanding conditions, the pressure of any excess flow supplied by this motor pump during voltage fluctuations in regular operation is controlled by the sub-assembly formed by the valves (VA7+PP1), which has a much higher level of dynamic response than traditional systems that use direct control via winches or motor pumps.

[0091]

[0052] The pressure reduction in the hydraulic accumulator (CA1), and consequently also in the hydraulic cylinder (CC1), during regular operation, is carried out with the directional valve (VD1) actuated (this remains actuated throughout the regular operation), and with a value determined by the proportional pressure valve (PP1) piloting the relief valve (VA7), which discharges part of the volume stored in the hydraulic accumulator (CA1), together with the flow supplied by the motor pump (MB5), if any, and any resulting difference, in the volume contained in the hydraulic cylinder (CC1).

[0092]

[0053] Returning to Figure 8, the pressure increase in the hydraulic accumulator (CA2), and consequently also in the hydraulic cylinder (CC2), during regular operation, is achieved with the directional valve (VD2) actuated, and with a value determined by the proportional pressure valve (PP2), which adjusts the desired increase over the minimum pressure manually defined in the relief valve (VA8), adjusted slightly below the preload value (PG2) of the hydraulic accumulator (CA2). The pressure of the relief valve (VA4) always remains adjusted to the maximum load value allowed in the hydraulic accumulator (CA4). An electric motor with a frequency inverter or other drive with the same features maintains the pump rotation (B6) at a level compatible with the dynamic requirements of each phase of regular operation.Since this pump is powered by the hydraulic accumulator (CA4), its function is solely to perform a pressure boost when necessary, consuming power only for this purpose, resulting in much lower installed power compared to traditional systems for the same level of response. In situations requiring high precision and very high dynamics, the motor pump (MB6) maintains rotation with excess flow at any given moment. Under these demanding conditions, the pressure of any excess flow supplied by this motor pump during voltage fluctuations in regular operation is controlled by the sub-assembly formed by the valves (VA8+PP2), which has a much higher level of dynamic response than traditional systems that use direct control via winches or motor pumps.

[0093]

[0054] The pressure reduction in the hydraulic accumulator (CA2), and consequently also in the hydraulic cylinder (CC2), during regular operation, is carried out with the directional valve (VD2) actuated (this remains actuated throughout the regular operation), and with a value determined by the proportional pressure valve (PP2) piloting the relief valve (VA8), which discharges part of the volume stored in the hydraulic accumulator (CA2), together with the flow supplied by the motor pump (MB6), if any, and any resulting difference, in the volume contained in the hydraulic cylinder (CC2).

[0094]

[0055] For equivalent dynamic response levels, in tensioning adjustments during regular operation, traditional systems also use valve controls, but in systems with high installed power, as they do not have energy storage for the main drive. Therefore, the solution presented here, for tensioning in regular operation, simultaneously allows active control (independent of the hydraulic cylinder position), with high dynamic response capacity and precision, and high energy efficiency. In addition, the motor pumps (MB5 and MB6) can also operate, in regular operation, with strict on-demand supply, in cases of lower dynamic demand and within their response capacity, with their respective rotation constantly adjusted to meet the exact demand of the moment.The shut-off valves (VB1 and VB2) function to protect the pumps (B5 and B6), respectively, from any excess flow coming from the hydraulic accumulators (CA3 and CA4), a condition in which they automatically block the flow passage.

[0095]

[0056] According to an embodiment of the invention, each of the motor pumps (MB5, MB6, MB7, MB8) has a shaft to which a flywheel (V5, V6, V7, V8) is coupled, as a complementary form of energy storage, in conveyors that exhibit large periodic load differences when in regular operation.

[0096]

[0057] In this case, the energy storage in the hydraulic energy recovery accumulators (CA3 and CA4) can be complemented by the high-mass flywheel, represented by (V5) in the subassembly (MB5), and (V6) in the subassembly (MB6), which allow energy storage in mechanical form as shown in figures 7 and 8, respectively. This complementary feature becomes interesting in applications where a high increase in tension is required for a very short time and periodically.

[0097]

[0058] In regular tensioning operation on the left side of the moving carriage (350 and 450), illustrated in Figure 7, the hydraulic cylinder (CC1) fractions this side of the moving carriage (350 and 450), with a force proportional to the pressure existing in the connection line (C1), and redundantly limited by the relief valve (VA1). For this, its rod must be engaged directly in the moving carriage (350 and 450), or indirectly through the toothed bar (341) connected by the key (361), which is advanced by the hydraulic cylinder (CC5). Except in some maintenance and semi-automatic adjustment operations, the directional valve (VP1) remains without actuation, keeping the logic element (EL1) open, in any direction of movement of the hydraulic cylinder (CC1), as shown in Figure 7.

[0098]

[0059] Figure 10 illustrates the circuit for controlling the auxiliary hydraulic cylinders (CC3, CC5 and CC7) on the left side of the moving carriage (350). The hydraulic cylinder (CC3), used only with the tensioning elements shown in figures 3A and 3B, can also move the moving carriage (350), provided that its toothed bar (342) is engaged in the carriage (350) by the key (362), which is advanced by the hydraulic cylinder (CC7).

[0099]

[0060] When tensioning cylinders (CC1 and CC3) and their corresponding keyway cylinders (CC5 and CC7) need to be moved in maintenance mode with tension equal to or less than Tmin on the conveyor belt (351), and with manual or semi-automatic actuation, this must be performed only after closing the valves (RG1 and RG3) to avoid interference from the corresponding hydraulic accumulators as shown in Figure 7. Performing any of these maintenance movements using the electro-hydraulic control subassembly (MC1 or MC1A) requires that the logic element (EL1) has an opening pressure (spring load) of 0.2 bar or less, that the directional valve (VD0) is actuated to generate flow and pressure in the general supply line, and that the solenoid (VP1 B) is actuated, except for advancing the hydraulic cylinder rod (CC1).

[0100]

[0061] In addition to these conditions valid for all these movements, it is necessary to actuate the corresponding directional valve: (VD3), to move the hydraulic cylinder (CC3); (VD5), to move the hydraulic cylinder (CC5); (VD7) to move the hydraulic cylinder (CC7), and (VP1) together with (VD1), to move the hydraulic cylinder (CC1). In the latter case, illustrated in Figure 7, the advance of the hydraulic cylinder rod (CC1) occurs with it in regenerative connection, with flow controlled by the internal jet in (EL1) and with the solenoid (VP1A) actuated. The most typical situation for the occurrence of all the semi-automatic movements described here is the adjustment of the tension Tmin of the conveyor belt (351), using the configuration shown in Figures 3A and 3B.With the tensioning configuration shown in Figures 4A and 4B, the auxiliary hydraulic cylinders (CC3, CC5, and CC7) are omitted, leaving only occasional manual movements of the hydraulic cylinder (CC1) in other maintenance situations. If a manual or semi-automatic adjustment of the Tmin tension value is desired after the initial adjustment, this can be performed using logic analogous to that of the regular automatic operation system, simply by increasing or decreasing the pressure set for the proportional pressure valve (PP1).

[0101]

[0062] In regular tensioning operation on the right side of the moving carriage (350 and 450), illustrated in figure 8, the hydraulic cylinder (CC2) fractions the moving carriage (350 and 450) with a force proportional to the pressure existing in the connection line (C2), and redundantly limited by the relief valve (VA2). For this, its rod must be engaged directly in the moving carriage (350 and 450), or indirectly through the toothed bar (344) connected by the key (364), which is advanced by the hydraulic cylinder (CC6). Except in some maintenance and semi-automatic adjustment operations, the directional valve (VP2) remains without actuation, keeping the logic element (EL2) open, in any direction of movement of the hydraulic cylinder (CC2).

[0102]

[0063] Figure 11 illustrates the circuit for controlling the auxiliary hydraulic cylinders (CC4, CC6 and CC8) on the right side of the moving carriage (350). The hydraulic cylinder (CC4), used only with the tensioning device shown in Figures 3A and 3B, can also move the moving carriage (350), provided that its toothed bar (343) is engaged in the carriage (350) by the key (363), which is advanced by the hydraulic cylinder (CC8).

[0103]

[0064] When moving the tensioning cylinders (CC2 and CC4), as well as the corresponding keyway cylinders (CC6 and CC8), in maintenance mode with tension equal to or less than Tmin on the conveyor belt (351), and with manual or semi-automatic actuation, this must be performed only after closing the valves (RG2 and RG4), to avoid interference from the corresponding hydraulic accumulators. Performing any of these maintenance movements using the electro-hydraulic control subassembly (MC2 or MC2A) requires that the logic element (EL2) has an opening pressure (spring load) of 0.2 bar or less, that the directional valve (VDO) is actuated to generate flow and pressure in the general supply line, and that the solenoid (VP2B) is actuated, except for advancing the hydraulic cylinder rod (CC2).

[0104]

[0065] In addition to these conditions valid for all these movements, it is necessary to actuate the corresponding directional valve: (VD4), to move the hydraulic cylinder (CC4); (VD6), to move the hydraulic cylinder (CC6); (VD8) to move the hydraulic cylinder (CC8), and (VP2) together with (VD2), to move the hydraulic cylinder (CC2). In the latter case, the advance of the hydraulic cylinder rod (CC2) occurs with it in regenerative connection, with flow controlled by the internal jet in (EL2) and with the solenoid (VP2A) actuated. The most typical situation for the occurrence of all the semi-automatic movements described here is the adjustment of the tension Tmin of the conveyor belt (351), using the configuration shown in Figures 3A and 3B.With the tensioning configuration shown in Figures 4A and 4B, the auxiliary hydraulic cylinders (CC4, CC6, and CC8) are omitted, leaving only occasional manual movements of the hydraulic cylinder (CC2) in other maintenance situations. If a manual or semi-automatic adjustment of the Tmin tension value is desired after the initial adjustment, this can be performed using logic analogous to that of the regular automatic operation system, simply by increasing or decreasing the pressure set for the proportional pressure valve (PP2).

[0105]

[0066] According to an embodiment of the invention, the tensioning device has a configuration expansion for use in medium-distance conveyors, where it is possible to pre-tension the conveyor belt (551) manually, semi-automatically or automatically during the initial commissioning of the conveyor, combined with the complementary subassemblies (MC7A, MC8A, CC5, CC6), and with the auxiliary mechanisms (501, 502), wherein in the regular operation of this expansion of the basic configuration, at least one cylinder or a series of hydraulic operating cylinders (CC1, CC2) fractions the mobile carriage (550) that tensions the conveyor belt (551), for which purpose it is engaged, at the other end, in a toothed bar (541 and 544) by means of the key (561, 564), which is kept advanced by the auxiliary hydraulic keying cylinder (CC5, CC6), wherein in the pre-tensioning of the belt or in maintenance activities,The movement of the mobile carriage (550) is achieved in stages through the cyclical and simultaneous actuation of the operating hydraulic cylinders (CC1, CC2). The mobile carriage is locked independently, also involving the auxiliary keyway cylinders (CC5, CC6) for engaging or disengaging each toothed bar, according to the moment of the movement cycle. Each maintenance movement is executed with the valves (RG1, RG3) closed, with the 4 / 3 directional valve (VDO) actuated, and with one of the solenoids of the 4 / 2 directional valves (VP3, VP7) actuated, according to the movement. It is necessary to actuate the specific directional valve for each movement: auxiliary keyway directional valve (VD5, VD6) to move the auxiliary keyway hydraulic cylinder (CC5, CC6), respectively, and blocking directional valve (VD1, VD2) to move the operating hydraulic cylinder (CC1, CC2), respectively.

[0106]

[0067] Figures 12A and 12B show a variant of the Tmin tensioning mode of the conveyor belt (551) using toothed bars (541 for mechanism 501; 544 for mechanism 502), in an application where there is no lateral space to accommodate these bars. Two intermittently actuating hydromechanical mechanisms (501 and 502) are illustrated, for splitting the carriage (550), which drives the drum (552). Each of these mechanisms is actuated, manually, semi-automatically or automatically, by hydraulic cylinders in series connected to it (CC1A or CC1B, for mechanism 501; CC2A or CC2B, for mechanism 502) which are connected at the opposite end to the tensioning carriage (550) via a connecting rod (523 and 524) with ball joints, each cylinder consisting of a sleeve (534), a rod (535), a ball joint (533) and an articulated fork (536). Thus, this series of cylinders is anchored and articulated to the tensioning carriage (550), and allows the respective side of the carriage (550) to be moved in stages.This occurs through the toothed bars (541 for mechanism 501; 544 for mechanism 502). The engagement and release of each toothed bar, at the base (500), anchored to the conveyor structure, is performed by another cylinder (CC5 for mechanism 501; CC6 for mechanism 502), positioned at 90° in relation to the tensioning series, by means of the positioning of the corresponding key (561 and 564), guaranteed by redundant electrical sensing. Each displacement step of each toothed bar corresponds to an increment of traction of the moving carriage (550), which tensions the conveyor belt (551). For this purpose, it is possible to use the auxiliary subassemblies shown in Figures 16 and 17 (detailed later). In most common cases of structural rigidity, simultaneous displacement of the toothed bars will be necessary at each stage, requiring the tensioning carriage (550) to have a locking device that can be effective in any position it is in.The mobile support vehicles (537, 538 and 539) move on two wheels each, which are supported and guided on two parallel rails.

[0107]

[0068] Figures 12A and 12B also illustrate the variant arrangement of hydraulic cylinders in simple series, which allows for long-stroke stretching applications, in case the use of winches is not accepted as an auxiliary device.

[0108]

[0069] According to an embodiment of the invention, the tensioning device has a special configuration and arrangement of at least two hydraulic operating cylinders (CC1, CC2) with characteristics of high longitudinal compactness, thus allowing it to meet applications where the space for installation is reduced also in the central tensioning region, such as in some cases of safety upgrades in conveyors, eliminating original gravity tensioners (counterweight), using a compact series of pairs of hydraulic operating cylinders (CC1A with CC2A, CC1B with CC2B, CC1C with CC2C, CC1D with CC2D), each pair of hydraulic operating cylinders having mechanical rigidity between them, with corresponding mechanical structures (610, 611, 613, 614), guaranteeing simultaneous action within each pair, to divide the carriage (650), which drives the drum (652), moving guided on parallel rails by means of wheels (653),wherein the compact series of cylinders is anchored to the conveyor structure.

[0070] Figures 13A and 13B show a way to perform the tensioning Tmin of the conveyor belt (651), using a compact series of four pairs of hydraulic cylinders (CC1 A with CC2A, CC1 B with CC2B, CC1C with CC2C, CC1D with CC2D), each cylinder consisting of a sleeve (634) and a rod (635). Each pair of hydraulic cylinders has mechanical rigidity between them, with corresponding mechanical structures (610, 611, 613 and 614), ensuring simultaneous actuation within each pair, to drive the carriage (650), which drives the drum (652), and moving guided on parallel rails by means of wheels (653). In this arrangement, the compact series of cylinders is anchored to the conveyor structure via a connecting rod (623 and 624), with ball joints (625, 626, 627 and 628), connected to the fixed base (600).and allows the tensioning carriage (650) to be moved to any position at any time. The compact form of this arrangement makes it suitable for applications where installation space is limited, even in the central tensioning area, such as in some cases of safety upgrades on conveyors, eliminating the original gravity tensioners (counterweight).

[0109]

[0071] Figures 14 and 15 show a variant of the sets presented in Figures 7 and 8, where essentially the following adjustments were introduced:

[0110]

[0072] To allow for easy later implementation of the operational energy storage system in applications where it is not initially desired (energy savings and reduced installed power are increasingly attractive features), but still allowing for the other features of the invention, the remaining system components are appropriately separated into modules that can operate adequately in both the initial and final conditions. In this sense, the control subassemblies (MC1 and MC2) are partitioned, generating four subassemblies (MC1A, MC1B, MC2A, and MC2B). The subassemblies (MC1B and MC2B) contain only the components responsible for performing the operational hydraulic energy storage, and the pumping subassemblies (MB5 and MB6) are fitted with the higher installed power and bidirectional pump required in the initial configuration, generating the corresponding subassemblies (MB7 and MB8).Therefore, it will only be necessary to include the subsets (MC1B and MC2B), rearrange the interconnections accordingly, and replace the software.

[0111]

[0073] In the initial configuration possible with this arrangement, the pressure change in the hydraulic accumulators (CA1 and CA2), and consequently also in the corresponding hydraulic cylinder (CC1 and CC2), during regular operation, is carried out with the directional valve (VD1 and VD2) actuated, and adjusted at each moment by the direction and magnitude of the pump rotation (B7 and B8) and by monitoring the pressure transducer (PC1 and PC2), both for pressure increases and decreases. An electric motor with frequency inverter, or other drive with the same features, maintains the pump rotation (B5) at a level compatible with the dynamic requirements of each phase of regular operation.

[0112]

[0074] The sequence of 4 / 2 directional valves (VP3 and VP7 in the MC1B subassembly; VP4 and VP8 in the MC2B subassembly) performs the same functions as the corresponding 4 / 3 directional valve (VP1 in the MC1B subassembly; VP2 in the MC2B subassembly), but enables the inclusion of a relief valve (VP9 in the MC1B subassembly; VP10 in the MC2B subassembly) that allows limiting the hydraulic cylinder pressure, when it is subjected to compression, to a value lower than the tensile pressure. This is relevant for structural safety in applications where the rod is very long.

[0113]

[0075] The inclusion of the blocking valve (VB3 in the MC1 B subassembly; VB4 in the MC2B subassembly) and the pressure transducer (PD1 in the MC1B subassembly; PD2 in the MC2B subassembly) aims to allow for emergency blocking of belt tensioning and its monitoring, in addition to the already implemented directional valve (VD1 in the MC1B subassembly; VD2 in the MC2B subassembly), as an alternative safety redundancy in applications where the tensioning carriage does not have a locking device in case of power failure or for parking.

[0114]

[0076] According to one embodiment of the invention, the tensioning device comprises a braking valve (VF1, VF2) that allows its load to be discharged to a value lower than an operating pressure, after a time lag in relation to a possible power outage, said lag being determined by at least one time accumulator (CA7, CA8) and by at least one jet (G11, G21).

[0115]

[0077] The inclusion of the braking valve (VF1 in subassembly MC1 B; VF2 in subassembly MC2B), together with the accumulator (CA7 in subassembly MC1B; CA8 in subassembly MC2B) and the jet (G11 in subassembly MC1B; G21 in subassembly MC2B) aims to allow a pressure reduction with a controlled ramp, after the discharge of the emergency accumulator (CA5) through the check valve (VR5 in subassembly MC1 B; VR6 in subassembly MC2B) during emergency stops, being relevant in long-distance belt conveyors.

[0116]

[0078] Figures 16 and 17 show a variant of the assemblies shown in Figures 10 and 11, where essentially the control subassemblies (MC7 and MC7) are partitioned, generating 4 subassemblies (MC7A, MC7B, MC8A and MC8B). This partitioning, while maintaining the same components and functions, allows for the suppression, when desired, of unused components in applications with a single keyway on each side, as in the case of Figures 12A and 12B.

[0117]

[0079] Figure 18 is a block diagram representing an example of incorporating the second constructive configuration of the tensioning device, and its interconnections, with the constituent subassemblies of the full variants presented in Figures 14, 15, 16 and 17, including the controls for 2 auxiliary stage actuation devices, on each side of the tensioner.

[0118]

[0080] Figure 19 is a block diagram of the constituent subassemblies of the hydraulic control configuration that represents an example of incorporating the first constructive configuration of the tensioning device, and its interconnections, suppressing the subassemblies responsible for storing operational energy (MC1B and MC2B) and with controls for a single auxiliary device for step actuation, on each side of the tensioner, when necessary.

[0119]

[0081] Figure 20 is a block diagram of the constituent subassemblies of the hydraulic control configuration representing another example of incorporating the first constructive configuration of the tensioning device, for four sets of actuators chained in compact series, and without controls for auxiliary devices, as in Figures 14A and 14B, and their interconnections - variant without the operational energy storage system, and without controls for auxiliary devices. Subassemblies MB7A, MB7B, MB7C and MB7D are replicas of the same subassembly MB7.

[0120]

[0082] The configurations in Figures 19 and 20 present simplified solutions for applications where there is no immediate interest in operational energy storage systems, but allow for their easy inclusion in the future, in addition to maintaining the other features offered by this invention, such as active control (independent of the hydraulic cylinder position) and high dynamic response and precision.

[0121]

[0083] Relief valves (VAn), check valves (VRn), flow control valves (RFn), pilot-operated check valves (RPn), gate valves (RGn), pressure transducers (PRn), and other components contained in the diagrams of this presentation, and not addressed in this description, perform regular basic functions compatible with their symbology, mainly as standard safety elements and as resources for maintenance activities.

[0122]

[0084] Relief valves (VAn), check valves (VRn), flow control valves (RFn), pilot-operated check valves (RPn), gate valves (RGn), pressure transducer (PRn) and other components contained in the diagrams of this presentation, and not addressed in this description, perform regular basic functions compatible with their symbology, mainly as standard safety elements and as resources for maintenance activities.

[0123] Table 1 - List of components

[0124]

[0125]

[0126]

[0127]

[0128]

Claims

CLAIMS 1. “CONVEYOR BELT TENSIONING DEVICE”, the tensioning device comprising a mobile carriage (350, 450, 550, 650) fitted with a return or deflection drum (352, 452, 552, 652) of a conveyor belt (351, 451, 551, 651), at least one operating hydraulic cylinder (CC1, CC2) connected to the mobile carriage (350, 450, 550, 650) to move the mobile carriage (350, 450, 550, 650) and adjust a tension level of the conveyor belt (351, 451, 551, 651), at least one operating hydraulic accumulator (CA1, CA2) configured to share hydraulic pressure with at least one operating hydraulic cylinder (CC1, CC2), characterized by understanding at least one motor pump (MB5, MB6, MB7, MB8) having adjustable flow direction and velocity magnitude, and at least one electro-hydraulic control subassembly (MC1, MC2, MC1A, MC2A, MC1B, MC2B) hydraulically connected to at least one operating hydraulic cylinder (CC1, CC2) and to at least one motor pump (MB5, MB6, MB7, MB8), whereby at least one electro-hydraulic control subset (MC1, MC2, MC1A, MC2A, MC1B, MC2B) and at least one motor pump (MB5, MB6, MB7, MB8) are configured to, in real time, transfer to or remove from at least one operating hydraulic cylinder (CC1, CC2) a flow rate of hydraulic fluid obtained as a function of the flow direction and velocity magnitude of at least one motor pump (MB5, MB6, MB7, MB8), whereby, in an initial constructive configuration of the tensioning device, the hydraulic fluid flow originates from or is destined for a hydraulic reservoir, in settings distinct from the tensioning level of the conveyor belt (351, 451, 551, 651), or In a second constructive configuration of the tensioning device, at least one hydraulic energy recovery accumulator (CA3, CA4) is hydraulically connected to at least one motor pump (MB5, MB6, MB7, MB8) and to at least one electro-hydraulic control subassembly (MC1, MC2, MC1B, MC2B), and the hydraulic fluid flow originates from at least one hydraulic energy recovery accumulator (CA3, CA4) to supply hydraulic energy to at least one operating hydraulic cylinder (CC1, CC2) or is destined for at least one hydraulic energy recovery accumulator (CA3, CA4) for hydraulic energy storage, in different adjustments of the conveyor belt tensioning level (351, 451, 551, 651).

2. “CONVEYOR BELT TENSIONING DEVICE”, according to claim 1, characterized by comprising at least one relief valve (VA7, VA8) piloted by a respective proportional pressure valve (PP1, PP2), to perform a redundancy of pressure control of the operating hydraulic cylinders (CC1, CC2), and simultaneously provide a recovery of fluid volumes eventually removed from the operating hydraulic cylinders (CC1, CC2), which are directed to storage in the hydraulic energy recovery accumulators (CA3, CA4).

3. “CONVEYOR BELT TENSIONING DEVICE”, according to claim 1, characterized by comprising at least one check valve (VR9, VR10) to protect against reverse flow over the motor pump (MB5, MB6, MB7, MB8), when the motor pump (MB5, MB6, MB7, MB8) does not operate in a bidirectional manner.

4. “CONVEYOR BELT TENSIONING DEVICE”, according to claim 1, characterized in that the energy recovery accumulators (CA3, CA4) are protected from overload by a relief valve (VA3, VA4), the tensioning device further comprising a check valve (RG3, RG4) to hydraulically block the hydraulic energy recovery accumulator (CA3, CA4) in a watertight manner during maintenance activities, and protection against any excess discharge flow from the hydraulic energy recovery accumulator (CA3, CA4) by automatically blocking this flow through exclusively hydraulic sensing and actuation of a 2 / 2 directional valve (VB1, VB2).

5. “CONVEYOR BELT TENSIONING DEVICE”, according to claim 1, characterized by comprising a set of pressure transducers (PR1, PC1, PB5, PD1, PA3, P07, PR2, PC2, PB6, PD2, PA4, P08) to monitor pressure at key points of the electro-hydraulic control subassemblies (MC1, MC2, MC1A, MC2A, MC1B, MC2B), allowing precise tensioning controls at any time, and alarm and safety lockout routines in case of failure events.

6. “CONVEYOR BELT TENSIONING DEVICE”, according to claim 1, characterized by comprising a relief valve (VA1, VA2) to limit a maximum recoil pressure value of the operating hydraulic cylinder rods (CC1, CC2), and a relief valve (VA9, VA10) to limit a maximum advance pressure value of the operating hydraulic cylinder rods (CC1, CC2), during pre-tensioning or maintenance activities, wherein a check valve (RG1, RG2) allows for the tight blocking of the volume stored in the operating accumulators (CA1, CA2) during maintenance activities, and a braking valve (VF1, VF2) allows for the discharge of its charge to a value lower than the operating pressure, after a time lag in relation to a possible power outage, said lag being determined by at least one timer accumulator (CA7, CA8) and by at least one jet. (G11, G21).

7. “CONVEYOR BELT TENSIONING DEVICE”, according to claim 1, characterized by comprising a normally closed, 2 / 2 directional shut-off valve (VD1, VD2) for blocking oil flow, in the absence of electrical control, between the hydraulic actuation subassemblies (CC1+PC1+CA1 and CC2+PC2+CA2) and their respective control components, a shut-off valve (RG7, RG8) to isolate the operating hydraulic cylinder (CC1, CC2) and / or a shut-off valve (RG9, RG10) to discharge the volume stored in that region to the hydraulic reservoir during an emergency stop, rest period or maintenance activities, and wherein a shut-off valve (VB3, VB4), actuated by internal differential pressure control, allows a function to block excess flow from the operating hydraulic cylinders (CC1, CC2) during the extension of their rods, redundant to that already permitted. electrically,with the pressure transducers (PC1 and PD1 on valve VD1; PC2 and PD2 on valve VD2).

8. “CONVEYOR BELT TENSIONING DEVICE”, according to claim 1, characterized by each of the motor pumps (MB5, MB6, MB7, MB8) having a shaft to which a flywheel (V5, V6, V7, V8) is coupled, as a complementary form of energy storage, in conveyors that present large periodic load differences when in regular operation.9.“CONVEYOR BELT TENSIONING DEVICE”, according to claim 1, characterized by the moving carriage (350, 450) comprising four pairs of wheels (353, 453), which move on two parallel rails (TR1), each pair in the same plane of travel, which is articulated in relation to the body of the moving carriage (350, 450), around a pivot center (CG1), up to a limit of the travel clearances (FG1), to allow a deviation of perpendicularity between a drum axis (352, 452) and a conveyor belt transport axis (351, 451), generated by differential tensioning between the two sides (left and right) of the moving carriage (350, 450), actuated respectively by the operating hydraulic cylinders (CC1, CC2), directly or indirectly, each having an active and independent electro-hydraulic control, during regular operation. of the conveyor belt, aiming to compensate for misalignments in this belt.

10. “CONVEYOR BELT TENSIONING DEVICE” according to claim 1, characterized by having logic elements (EL1, EL2), hydraulically connected to the operating hydraulic cylinders (CC1, CC2), to draw hydraulic fluid from the hydraulic reservoir when the operating hydraulic cylinders (CC1, CC2) are reducing the tension of the conveyor belt (351, 451, 551, 651), with the pilot directional valves (VP1, VP2, VP3, VP4, VP7, VP8) being deactivated, when said logic elements (EL1, EL2) have adequate opening pressure for said suction function, when the check valves (VR3, VR4) block the access of atmospheric pressure existing in the hydraulic reservoir to the logic elements (EL1, EL2), and in the reverse movement, when the operating hydraulic cylinders (CC1, CC2) need to expel the suctioned fluid, monitored by the pressure transducers (PR1, PR2),When the conveyor belt tension increases (351, 451, 551, 651), the logic elements (EL1, EL2) also open, and the fluid contained in the pilot chamber of the logic elements (EL1, EL2) is discharged to the hydraulic reservoir, along with the flow through the jet of its piston, passing through the center of the pilot directional valves (VP1, VP2, VP3, VP4, VP7, VP8) and the check valves (VR3, VR4), which allows the logic elements (EL1, EL2) to open.

11. “CONVEYOR BELT TENSIONING DEVICE”, according to claim 1, characterized by having an emergency hydraulic accumulator (CA5) for emergency stops, its pressure monitoring transducer (PA5), an auxiliary pumping subassembly (MBO), which provides the initial hydraulic charge of the operating hydraulic accumulators (CA1, CA2), energy recovery accumulators (CA3, CA4) and emergency accumulator (CA5), and an electro-hydraulic control subassembly (MC3), which together with the pressure transducers (PAO, PBO, PA3, PA4, PA5), the pressure gauge (MNO), and its isolation register (RBO), provides control of the minimum hydraulic charge of said accumulators (CA1, CA2, CA3, CA4, CA5), in addition to controlling the actuation of the operating hydraulic cylinders (CC1, CC2) in emergency stops, the emergency hydraulic accumulator being... (CA5) remains inactive, despite being loaded, during regular conveyor operation.Entering the operating circuit of the hydraulic cylinders (CC1, CC2) automatically during emergency power outages, the control valve (VC5) opens in a ramped fashion, with its time controlled by a jet (G50) that controls the flow rate of the valve (VC5) actuation, from the moment its 4 / 2 pilot directional valve (VP5) is switched off by the power outage. The opening of the control valve (VC5) provides a direct connection of the emergency hydraulic accumulator (CA5) to the operating hydraulic cylinder (CC1, CC2) and the operating hydraulic accumulators (CA1, CA2), without interference from the energy recovery hydraulic accumulators (CA3, CA4), which are isolated by the automatic blocking of the 2 / 2 blocking directional valves (VD1, VD2) during a power outage. In a regular (non-emergency) shutdown event...The 4 / 2 directional valve (VD9) is activated at the beginning of this shutdown and remains activated until its end, allowing the complete discharge of the fluid stored in the emergency hydraulic accumulator (CA5) through the compensated jet (GC9). The emergency hydraulic accumulator (CA5) has a relief valve (VA5) to limit its maximum charge and a gate valve (RG5) to securely block the volume stored in the emergency hydraulic accumulator (CA5) during maintenance activities.

12. “CONVEYOR BELT TENSIONING DEVICE”, according to claim 1, characterized by having a configuration expansion for use in medium-distance conveyors, to perform a pre-tensioning of the conveyor belt (351), manually, semi-automatically or automatically, during the initial adjustment of the conveyor, combined with the complementary subassemblies (MC7, MC8), with auxiliary hydraulic tensioning cylinders (CC3, CC4) and auxiliary hydraulic keying cylinders (CC5, CC6, CC7, CC8), and with the auxiliary hydromechanical keying mechanisms (301, 302), wherein in the regular operation of this expansion of the basic configuration, the operating hydraulic cylinders (CC1, CC2) fraction the moving carriage (350) that tensions the conveyor belt (351), indirectly through toothed bars (341, 344) connected by keys (361, 364),which are kept advanced by the auxiliary hydraulic cylinders for keying (CC5, CC6), and the auxiliary hydraulic cylinders for tensioning (CC3, CC4) also move the mobile carriage (350) during maintenance activities with tension below the minimum required for regular operation of the conveyor belt (351), provided that its toothed bars (342, 343) are engaged in the carriage (350) by the keys (362, 363), which are advanced by the auxiliary hydraulic cylinders for keying (CC7, CC8), and in maintenance activities, a displacement of the mobile carriage (350) is obtained in stages, through the alternating and cyclical action between the operating cylinders (CC1, CC2) and the auxiliary tensioning cylinders (CC3, CC4), also involving the keying cylinders (CC5, CC6, CC7, CC8) for the engagement or release of each toothed bar (341, 342, 343, 344), according to the moment in the displacement cycle,whereby each of these maintenance movements is performed with the valves (RG1, RG3) closed, with the 4 / 3 directional valve (VD0) actuated, and with a directional valve solenoid (VP1, VP2, VP3, VP4, VP7, VP8) actuated, according to the movement, and requiring the actuation of the specific directional valve for each movement: auxiliary tensioning directional valve (VD3, VD4), to move the auxiliary tensioning hydraulic cylinders (CC3, CC4) respectively; auxiliary keyway directional valve (VD5, VD6, VD7, VD8), to move the auxiliary keyway hydraulic cylinders (CC5, CC6, CC7, CC8) respectively; and the electric directional valves (VP1, VP2, VP3, VP4, VP7, VP8) together with the blocking directional valves (VD1, VD2), to move the operating hydraulic cylinders (CC1, CC2) respectively.

13. “CONVEYOR BELT TENSIONING DEVICE”, according to claim 1, characterized by having a configuration expansion for use in medium-distance conveyors, where it is possible to pre-tension the conveyor belt (551) manually, semi-automatically or automatically during the initial commissioning of the conveyor, combined with the complementary subassemblies (MC7A, MC8A), with the auxiliary hydraulic cylinders for keying (CC5, CC6), and with the auxiliary mechanisms (501, 502), wherein in the regular operation of this expansion of the basic configuration, at least one cylinder or a series of operating hydraulic cylinders (CC1, CC2) fractions the movable carriage (550) that tensions the conveyor belt (551), for which purpose it is engaged, at the other end, in a toothed bar (541, 544) through the key (561, 564), which is kept advanced by the auxiliary hydraulic cylinder of keyway (CC5, CC6),In the case of belt pre-tensioning or maintenance activities, the mobile carriage (550) is moved in stages through the cyclical and simultaneous action of the operating hydraulic cylinders (CC1, CC2). The mobile carriage is locked independently, also involving the auxiliary keyway cylinders (CC5, CC6) for engaging or disengaging each toothed bar, according to the moment of the displacement cycle. Each maintenance movement is performed with the valves (RG1, RG3) closed, the 4 / 3 directional valve (VDO) actuated, and a directional valve solenoid (VP1, VP2, VP3, VP4, VP7, VP8) actuated, according to the movement. It is necessary to actuate the specific directional valve for each movement: auxiliary keyway directional valve (VD5, VD6) to move the auxiliary keyway hydraulic cylinder (CC5, CC6), and the blocking directional valve (VD1, VD6). VD2),to move the operating hydraulic cylinder (CC1, CC2) respectively.

14. “CONVEYOR BELT TENSIONING DEVICE”, according to claim 1, characterized by having a configuration expansion for use in long-distance conveyors or conveyors with high elasticity under tension, to perform a pre-tensioning of the conveyor belt, manually, semi-automatically or automatically, during the initial commissioning of the conveyor, using the operating hydraulic cylinders (CC1, CC2) to directly divide the moving carriage (450), with its other ends articulated in an intermediate moving carriage (440), which in turn is kept divided by an electric or hydraulic winch (411, 412), anchored to the fixed structure of the conveyor, through a base (400), this winch acting only to perform the pre-tensioning of the conveyor belt (451), remaining inactive and braked during the regular operation of the conveyor.

15. “CONVEYOR BELT TENSIONING DEVICE”, according to claim 1, characterized by having a special configuration and arrangement of at least two operating hydraulic cylinders (CC1, CC2) with high longitudinal compactness characteristics, thus allowing it to meet applications where the installation space is also reduced in the central tensioning region, such as in some cases of safety upgrades in conveyors, eliminating original gravity tensioners (counterweight), using a compact series of pairs of operating hydraulic cylinders (CC1A with CC2A, CC1B with CC2B, CC1C with CC2C, CC1D with CC2D), each pair of operating hydraulic cylinders having mechanical rigidity between them, with corresponding mechanical structures (610, 611, 613, 614), guaranteeing simultaneous action within each pair, to divide the carriage (650), which drives the drum (652),moving along parallel rails guided by wheels (653), with the compact series of cylinders anchored to the conveyor structure.

Images